docs: def _add_gene_equivalencies(self, xrefs, gene_id, taxon):
          """
          Add equivalentClass and sameAs relationships
  
          Uses external resource map located in
          /resources/clique_leader.yaml to determine
          if an NCBITaxon ID space is a clique leader
          """
  
          clique_map = self.open_and_parse_yaml(self.resources['clique_leader'])
  
          if self.test_mode:
              graph = self.testgraph
          else:
              graph = self.graph
          model = Model(graph)
          filter_out = ['Vega', 'IMGT/GENE-DB', 'Araport']
  
          # deal with the dbxrefs
          # MIM:614444|HGNC:HGNC:16851|Ensembl:ENSG00000136828|HPRD:11479|Vega:OTTHUMG00000020696
  
          for dbxref in xrefs.strip().split('|'):
              prefix = ':'.join(dbxref.split(':')[:-1]).strip()
              if prefix in self.localtt:
                  prefix = self.localtt[prefix]
              dbxref_curie = ':'.join((prefix, dbxref.split(':')[-1]))
  
              if dbxref_curie is not None and prefix != '':
                  if prefix == 'HPRD':  # proteins are not == genes.
                      model.addTriple(
                          gene_id, self.globaltt['has gene product'], dbxref_curie)
                      continue
                      # skip some of these for now based on curie prefix
                  if prefix in filter_out:
                      continue
  
                  if prefix == 'ENSEMBL':
                      model.addXref(gene_id, dbxref_curie)
                  if prefix == 'OMIM':
                      if DipperUtil.is_omim_disease(dbxref_curie):
                          continue
                  try:
                      if self.class_or_indiv.get(gene_id) == 'C':
                          model.addEquivalentClass(gene_id, dbxref_curie)
                          if taxon in clique_map:
                              if clique_map[taxon] == prefix:
                                  model.makeLeader(dbxref_curie)
                              elif clique_map[taxon] == gene_id.split(':')[0]:
                                  model.makeLeader(gene_id)
                      else:
                          model.addSameIndividual(gene_id, dbxref_curie)
                  except AssertionError as err:
                      LOG.warning("Error parsing %s: %s", gene_id, err)
          return